列出分組在一起的mysql數據，並為每個組顯示num_rows

Question

我有從表中選擇行並按類別列將它們分組在一起的此SQL代碼

echo '<strong>Categories</strong><br>';
    $sql="SELECT * from tickets where deleted = '' and DAY(datetime) = '04' and MONTH(datetime) = '".date("m")."' and YEAR(datetime) = '".date("Y")."' group by category order by datetime ASC ";
    $rs=mysql_query($sql,$conn);
    while($result=mysql_fetch_array($rs))
    {
        echo $result["category"].' ('.mysql_num_rows($rs).')<br>';
    }

當顯示行數時，每行顯示相同的數字。

我如何才能在每個“類別”旁邊顯示正確的數字？

Answer 1

SELECT *, COUNT(category) AS my_groupcount from tickets

echo $result["category"].' ('.$result["my_groupcount"].')<br>';

Answer 2

您可能想要執行這樣的查詢，其中您要使用COUNT函數來告訴您每個類別分組中有多少票證。

SELECT  category, COUNT(id) AS NumTickets, MIN(datetime) AS FirstDateTime
FROM tickets 
WHERE deleted = '' AND DAY(datetime) = 4 AND
        MONTH(datetime) = 12 AND YEAR(datetime) = '2012' 
GROUP BY category 
ORDER BY MIN(datetime)